The invention relates to the steam cooking of shrimp and, more particularly, to methods for steam cooking shrimp at reduced temperatures to decrease yield loss in cooked product.
In the bulk processing of shrimp, it is well known to cook shrimp in water baths or steam environments. Shrimp may be cooked in batches in a cooking vessel or continuously transported through an open-ended cooking chamber by a conveyor belt. In many of the batch cookers and some of the continuous cookers, the cooking occurs at elevated pressures. In continuous cookers that are open to the atmosphere and operate at atmospheric pressure, the conventional practice has been to cook shrimp with steam or steam/air mixtures at 212.degree. F. (100.degree. C.). In order to speed up the cooking time, higher temperatures and pressures have conventionally been used.
Cooking shrimp with steam or a steam/air mixture is described in a number of patents: U.S. Pat. No. 3,501,317 to Veltman (at elevated pressure and temperatures from about 220.degree. F. to 260.degree. F.); U.S. Pat. No. 4,340,613 to Moore (at elevated pressure in a retort at temperatures up to 250.degree. F.); U.S. Pat. No. 4,887,524 to Ellis-Brown (at elevated pressure); U.S. Pat. No. 4,862,794 to Lapeyre et al. and U.S. Pat. No. 5,184,538 to Ledet (with saturated steam at 212.degree. F. (100.degree. C.)); and U.S. Pat. No. 5,156,873 to Skrmetta (with air/steam mixture at 212.degree. F. (100.degree. C.) in distinct cooking zones). In all of these patents, steam cooking of shrimp at or above 212 F. (100.degree. C.) is taught as desirable.
As reported in the Veltman patent, it is known that cooking shrimp in water or brine at reduced temperatures, e.g., from 170.degree. F. to 212.degree. F., results in a substantial weight loss. The practice of cooking at high temperatures to reduce cooking time and yield loss has been adopted by both steam cooking processors and water cooking processors.
Owing to the relatively high price of shrimp by weight, the loss of weight in the final cooked product is costly to the shrimp processor. Any decrease in weight loss directly benefits the processor. Consequently, a process or method of commercially cooking shrimp that decreases weight loss would be pleasing to the shrimp processing industry.
The object of the invention is to increase the yield of cooked shrimp through a cooking process that decreases the loss of weight during cooking. Another object of the invention is to cook at atmospheric pressure to eliminate the need for seals or excess steam emission.